A system constituted from a core and edges is known as one form of storage network systems. In this system, a plurality of storage sites are connected to each other via a network and a site playing a central role is the core and sites other than the core are the edges. As a specific form of the core-edge system, there is an example where a core is a data center and edges are remote offices.
A data file is first created at an edge and the core plays a role to intensively back up and archive data and files in the plurality of edges. File operations such as creation, use, and manipulation of files are executed by the edges. Therefore, a storage system existing at the edge is connected to a plurality of client terminals.
Furthermore, as a specific form of the core-edge system, there is a medical data management system at hospitals. Edges are medical institutions of various sizes and a core is a large-scale data center that is established by the administrative authorities and exists in a local community.
The core plays a role to receive medical data from each hospital, which is the edge, and back up and archive the received medical data, or enable reference to the medical data from other hospitals.
Hierarchical Storage Management (HSM) is applied in order to enhance efficiency of data management at both the edge and core sites. For example, a means of recognizing a series of actions involving creation, utilization, storage, and disposal of digital data as a life cycle and using an optimum storage unit, from among multiple tiers such as 1st Tier (first tier) (online), 2nd Tier (second tier) (near-line), and 3rd Tier (third tier) (archive), as appropriate at different times for the hierarchical management of the data according to an availability value of the data that changes over time is realized.
Incidentally, as conventional techniques relating to this invention, there are techniques disclosed in Japanese Patent Laid-Open (Kokai) Application Publication No. 2004-139471 and Japanese Patent Laid-Open (Kokai) Application Publication No. 2005-322020.